1. Field of the Invention
The present invention relates to a grommet and more specifically to a structure of a grommet for passing a wire bundle through a panel which partitions two compartments, for instance. The grommet of this kind is attached to a panel disposed between a first compartment (e.g. an engine room of an automotive vehicle) and a second compartment (e.g. a passenger compartment of an automotive vehicle) in order to pass a wire bundle or a cable through the panel without transmitting sound or water.
2. Description of the Prior Art
An example of noise prevention grommets is disclosed in Japanese Published Unexamined (Kokai) Utility Model Application No. 57-15626, as shown in FIGS. 1A and 1B.
This prior-art grommet G is composed of a grommet body a made of a synthetic resin and a noise insulating member b made of a foam plastic material. The grommet body a is formed with a large-diameter cylindrical portion a.sub.1 and a small-diameter cylindrical portion a.sub.2 and a funnel-shaped portion extending between the two cylindrical portions. Further, an annular groove a.sub.3 fittable to a panel P is formed along the outer circumferential surface of the large-diameter cylindrical portion a.sub.1.
The noise insulating member b is formed with a central hole b.sub.1 through which a cable or a wire bundle C is passed and a radial slit b.sub.2 for facilitating the insertion of the cable c thereto.
In the prior-art grommet G as described above, when the wire bundle c is required to be wired by use of the grommet G, the wire bundle c is first passed through the grommet body a; the noise insulating member b is attached to the wire bundle c by opening the slit b.sub.2 and then fitted to the large-diameter cylindrical portion a.sub.1 of the grommet body a; the wire bundle c and the grommet body a are fixed to each other by taping; lastly the grommet body a is fitted to the panel P with the annular groove a.sub.3 fitted to a hole formed in the panel P.
In the prior-art grommet, however, since spaces between the wire bundle c and the grommet body a or the noise insulating member b or between cable wires are not perfectly sealed, there exist various problems as follows: the noise prevention effect is not sufficient; the number of parts of the grommet G is large; the workability of mounting the grommet G to the panel is poor; water seeps from the left side (e.g. an engine room) to the right side (e.g. a passenger compartment) through the cable wires, thus degrading the foam material b and the resin material a; further, the wiring work is not productive because the wire bundle c is first fixed to the grommet body a by taping and then sealed thereto also by taping, in particular when the grommet is used in an assembly line of automotive vehicles.